translation of GPS trajectories

Hello, somebody could help me to solve the following problem? I have two GPS trajectories (lat, lon, h, UTC time) that tracks two moving vehicle (vehicle1 and 2). They are two cvs files for each. I need to generate an output that containing the trajectory relative to one another. obviously the coordinate are to be in X,Y,Z relative at the system reference of the first one vehicle. some saggestions or matlab code?

[Sean de Wolski]

What do you mean by trajectory relative to each other? Do you want the difference in direction/velocity/distance above sea level, all of the above?